Australia has urged China to handle the case of a Rio Tinto mining executive charged with industrial espionage openly and quickly. Stern Hu, an Australian citizen, was arrested in Shanghai last year with three other Rio Tinto employees.

Australia reacted cautiously to news that Rio Tinto executive Stern Hu and his three Chinese colleagues have been formally charged.

A foreign affairs spokesman in Canberra urged Beijing to handle the men's cases "transparently and expeditiously."

The four Rio Tinto employees have been in custody since last July. They were detained during sensitive iron ore contract talks and the Chinese prosecutors accuse them of soliciting or accepting large bribes.

Jerome Cohen, a professor of Chinese law at New York University, thinks there is little chance the men will avoid a conviction.

"The Chinese lawyers involved in the case are very able, experienced people but, of course, being Chinese criminal defense lawyers they do not have as much opportunity to defend their clients as they would in other systems," Cohen said. "The odds are very great now that these fellows are going to get convicted."

Although the news that the four were formally charged came Wednesday, a date for the trial, which is expected to be held in Shanghai, has not been set.

Rio Tinto, an Anglo-Australian mining corporation, has said it is not aware of any wrongdoing by its employees.

On Thursday, a Chinese Foreign Ministry spokesman said the legal rights of the Rio Tinto employees would be guaranteed.

The maximum penalty for commercial espionage in China is seven years in prison. Taking large bribes can bring a five-year sentence.

China is the world's biggest steel producer and consumer of iron ore, much of which is exported from Australian mines.

Australia's minerals industry has helped to insulate the country from the worst of the global economic slowdown.